JP2005039535A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader in which photodetectors are arranged at specified exact positions in a frame case. <P>SOLUTION: The image reader (A) comprises a substrate 5 in which a wiring pattern is formed on its surface; a plurality of sensor IC chips 7 mounted on the wiring pattern and provided with a plurality of built-in photodetectors 70; and a frame case 1 attached to the substrate 5. A pair of projection members 8 are mounted on the wiring pattern. By engaging the pair of projection members 8 with a pair of hole sections 1a formed on the frame case 1, positioning of the frame case 1 and the wiring pattern is carried out. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image reading apparatus used for reading a document image by being assembled in a facsimile or various scanners.

  As is well known, this type of image reading apparatus is generally configured by assembling predetermined necessary parts to a synthetic resin frame case (see, for example, Patent Document 1). FIG. 6 shows an example of such a conventional image reading apparatus. The illustrated image reading apparatus B is used for a so-called flat bed type scanner Sc, and is assembled with a movable frame F of the scanner Sc to display an image of a document D placed on a glass document table T. It is for reading. The image reading apparatus B has a configuration in which a substrate 105 is attached to the lower part of the frame case 101. A light source (not shown) is provided on the upper surface of the substrate 105, and a plurality of sensor IC chips 107 are mainly used. They are arranged in a line in the scanning direction (left-right direction in the figure). The light emitted from the light source is reflected by the document D, and the reflected light 111 is focused by the lens array 103, whereby a plurality of light receiving elements (not shown) built in the plurality of sensor IC chips 107 are illustrated. The image of the document D is formed on (above). Each light receiving element outputs an image signal of an output level corresponding to the amount of light received, and a read image is obtained by performing processing based on these signals.

The image reading apparatus B is positioned by the scanner Sc by aligning predetermined portions of the frame case 101 and the movable frame F with each other. The substrate 105 is fitted in a recess provided in the bottom of the frame case 101, and thereby positioning with respect to the frame case 101 is achieved. The plurality of sensor IC chips 107 are mounted on a wiring pattern (not shown) formed on the substrate 105.
JP-A-11-215301

  However, in the image reading apparatus B according to the conventional technique, the positional accuracy of the plurality of sensor IC chips 107 in the scanner Sc is inferior.

  Specifically, the substrate 105 is first positioned with respect to the frame case 101 by fitting the substrate 105 into a recess provided in the frame case 101. If the outer shape of the substrate 105 is inaccurate, the position of the substrate 105 with respect to the frame case 101 is shifted due to a gap between the recess and the substrate 105. In particular, when the substrate 105 is made of ceramic, when the substrate 105 is divided in the manufacturing process, the dividing surface is often accompanied by cracks, and the shape of the end surface is rough compared to, for example, a machined metal surface. Therefore, there is a possibility that the positional deviation will be increased.

  Further, although the wiring pattern on the substrate 105 can be formed in an accurate shape, the position of the entire wiring pattern may be shifted with respect to the substrate 105, which may be inaccurate. When the plurality of sensor IC chips 107 are mounted on such a wiring pattern, the positions of the plurality of sensor IC chips 107 on the substrate 105 also become inaccurate.

  Thus, if the position of the substrate 105 with respect to the frame case 101 and the position of the sensor IC chip 107 on the substrate 105 are inaccurate, even if the frame case 101 is correctly attached to the movable frame F, the sensor IC chip 107 Cannot be accurately placed at a predetermined position of the scanner Sc. If the sensor IC chip 107 is only displaced in the sub-scanning direction, it can be dealt with by finely adjusting the reading timing. However, if the position is shifted in the main scanning direction, it cannot be dealt with by adjusting the reading timing. Since the readable area Sa ′ by the image reading apparatus B is defined by the arrangement of the plurality of sensor IC chips 107, when the positional deviation in the main scanning direction occurs, the readable area Sa ′ in the scanner Sc. There is a possibility that the position becomes inappropriate. That is, in the scanner Sc, the maximum reading area Sx ′ in the main scanning direction is defined as the device specification, and it is desirable that the maximum reading area Sx ′ is included in the readable area Sa ′ as shown in FIG. . However, if the position of the readable area Sa ′ is inappropriate, the readable area Sa ′ is deviated from the maximum reading area Sx ′, and there is a possibility that the image cannot be read appropriately.

In order to deal with the above problem, it is necessary to provide surplus portions Sm ₁ ′ and Sm ₂ ′ in the readable area Sa ′ and sufficiently increase these surplus portions Sm ₁ ′ and Sm ₂ ′. However, in order to increase the surplus portions Sm ₁ ′ and Sm ₂ ′, it is necessary to increase the number of mounted sensor IC chips 107, resulting in an increase in cost. Further, as the number of light receiving elements increases, the processing amount of these signals increases, and the processing time required for image reading becomes longer. Further, when the size of the image reading apparatus B increases with the increase in the readable area Sa ′, there is a case where the request for downsizing the device to which the image reading apparatus B is assembled may not be satisfied.

  In the above prior art, the plurality of sensor IC chips 107 may be adversely affected by external electromagnetic waves. Specifically, for example, an electromagnetic wave shielding member can be arranged below the plurality of sensor IC chips 107, and electromagnetic waves from below the image reading apparatus B can be shielded by the shielding member. On the other hand, the transparent cover 102 and the lens array 103 provided above the plurality of sensor IC chips 107 do not have a shielding property. Further, it is difficult to dispose the shield member in the frame case without shielding the light 111 reflected from the document and without increasing the size of the image reading apparatus B. Therefore, it is difficult to appropriately shield the electromagnetic wave coming from above the image reading apparatus B, and there is a possibility that the plurality of sensor IC chips 107 may malfunction due to the influence of the electromagnetic wave.

  The present invention has been conceived under the circumstances described above, and provides an image reading apparatus capable of arranging a light receiving element at a predetermined accurate position with respect to a frame case. It is an issue.

  In order to solve the above problems, the present invention takes the following technical means.

  An image reading apparatus provided by the present invention includes a substrate having a wiring pattern formed on a surface thereof, a plurality of light receiving elements mounted on the substrate, and a frame case attached to the substrate. A reading device, wherein a plurality of projecting members are mounted on the wiring pattern, and the plurality of projecting members and a part of the frame case are fitted together, whereby the frame case and the wiring pattern It is characterized in that positioning is performed.

  According to such a configuration, since the protruding member is mounted on the wiring pattern, the positional relationship between the protruding member and the light receiving element is also achieved by mounting the plurality of light receiving elements on the wiring pattern. Can be accurate. In addition, the plurality of light receiving elements are accurately positioned with respect to the frame case by fitting the protruding member and a part of the frame case. For this reason, if the frame case is accurately attached to a device in which the image reading apparatus is incorporated, the plurality of light receiving elements can be accurately arranged at predetermined positions of the device. Accordingly, the position of the readable area of the image reading apparatus in the device is appropriate, and is positioned at an accurate position with respect to the maximum reading area of the device, so that these regions do not deviate greatly. For this reason, there is no need to mount a large number of light receiving elements, which is suitable for cost reduction and processing time reduction. In addition, it is advantageous for reducing the size of a device to which the image reading apparatus is assembled. Furthermore, according to the present invention, it is not necessary to finish the outer shape of the substrate with high accuracy, and the requirement for the positional accuracy of the wiring pattern with respect to the substrate can be relaxed, so that improvement in productivity can be expected.

  In a preferred embodiment of the present invention, the plurality of protruding members are made of metal. According to such a configuration, these protruding members can be easily soldered on the wiring pattern. These projecting members can be made with good moldability and high strength.

  In a preferred embodiment of the present invention, the plurality of protruding members include a metal core material and a plating layer formed on the surface of the core material and having higher solder wettability than the core material. It is configured.

  According to such a configuration, for example, when the protruding member is mounted on the wiring pattern using solder reflow, a solder fillet can be appropriately formed, and the protruding member is firmly bonded to the substrate. be able to. Therefore, the attachment of the substrate to the frame case is ensured.

  In a preferred embodiment of the present invention, the frame case has magnetic permeability. According to such a structure, the electromagnetic wave from the outside can be suitably shielded by the frame case having the magnetic permeability. Therefore, it is possible to suppress the malfunction of the plurality of light receiving elements. Further, when the frame case is used as a shield member, there are no problems such as shielding light from the document and enlarging the image reading apparatus itself.

  In a preferred embodiment of the present invention, the frame case has conductivity. Alternatively, the frame case has a metal film formed on the surface of the resin main body.

  In a preferred embodiment of the present invention, any one of the plurality of protruding members is grounded.

  According to such a configuration, the frame case is grounded via the protruding member. Therefore, for example, even when the electromagnetic wave is shielded, the frame case is not charged, and malfunction of an IC chip or the like disposed around the frame case can be prevented.

  In a preferred embodiment of the present invention, the plurality of protruding members and a part of the frame case are in surface contact. According to such a configuration, the ground connection of the frame case is ensured.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

  Hereinafter, a preferred embodiment of the present invention will be specifically described with reference to the drawings.

  1 to 4 show an example of an image reading apparatus according to the present invention. The image reading apparatus A of the present embodiment is used as, for example, a component of a so-called flat bed type scanner Sc, and includes a frame case 1, a transparent cover 2, a lens array 3, a substrate 5, a plurality of LED chips 6, and a plurality of LED chips 6. The sensor IC chip 7 and the pair of protruding members 8 are provided.

  The frame case 1 is made of, for example, a synthetic resin in which about 7 to 10% by weight of carbon fiber is contained in an alloy of polycarbonate and ABS resin. When such a material is used, the frame case 1 has good moldability and has conductivity and magnetic permeability. The frame case 1 has a shape extending in the main scanning direction, and its outer shape is formed with high accuracy. By positioning and attaching a predetermined portion of the outer surface of the frame case 1 to a predetermined portion of the movable frame F of the scanner Sc, the image reading apparatus A is positioned in the scanner Sc. The movable frame F is for moving the image reading device A in the sub-scanning direction and reading the image of the entire document D.

  The transparent cover 2 is, for example, an elongated rectangular glass plate or synthetic resin plate in plan view, and is attached to the upper surface portion of the frame case 1. The lens array 3 is configured by holding a plurality of lenses 31 arranged in a row on a long block-shaped synthetic resin holder 30 extending in the main scanning direction. For example, each lens 31 may be a rod lens. Is used. The lens array 3 is assembled to the frame case 1 so as to face the back surface of the transparent cover 2.

  The plurality of sensor IC chips 7 is a semiconductor chip in which an integrated circuit including a plurality of light receiving elements 70 is built, and is arranged in a line connected in the main scanning direction and mounted on the surface of the substrate. . The plurality of sensor IC chips 7 are configured such that each light receiving element 70 can receive the light 11 that has passed through the lens array 3 by attaching the substrate 5 to the bottom of the frame case 1. Each light receiving element 70 has a photoelectric conversion function, and when receiving light on a predetermined light receiving surface, it outputs a signal (image signal) of a level corresponding to the amount of received light. The plurality of LED chips 6 are light sources for illuminating a document, and are arranged on the surface of the substrate 5 in a row parallel to the plurality of sensor IC chips 7 at a predetermined pitch. Light emitted from the plurality of LED chips 6 travels through an optical path 14 formed in the frame case 1, and is applied to the document D disposed on the glass document table T through the transparent cover 2. The surface that defines the optical path 14 is, for example, white, and has high light reflectance.

  The substrate 5 is made of, for example, ceramic and has a rectangular shape in plan view. A wiring pattern (not shown) for electrically connecting the plurality of LED chips 6 and the plurality of sensor IC chips 7 is provided on the surface of the substrate 5. The sensor IC chip 7 is mounted on this wiring pattern using, for example, a solder reflow technique. In addition, a connector for conducting power supply and inputting / outputting various signals to / from the plurality of LED chips 6 and the plurality of sensor IC chips 7 at one end of the substrate 5 is conducted to the wiring pattern. 60 is provided.

  2 and 3, a pair of protruding members 8 are provided on the surface of the substrate 5 so as to be separated from each other in the main scanning direction. The pair of projecting members 8 have a substantially cylindrical shape with a chamfered upper portion, and are fitted to a pair of holes 1 a formed in the frame case 1, thereby positioning the wiring pattern with respect to the frame case 1. It is for doing. As will be described later, the pair of protruding members 8 are mounted on the wiring pattern, and the position with respect to the wiring pattern is accurate. The pair of holes 1a are substantially conical, and can be formed at the same time when the frame case 1 is resin-molded, for example, and the size and position of the frame case 1 are accurate.

  4 is an enlarged view of a main part of FIG. The protruding member 8 includes, for example, a substantially cylindrical stainless steel core material 81 and a Ni alloy plating layer 82 formed on the surface of the core material 81. The protruding member 8 is mounted on the ground terminal 9 of the wiring pattern by, for example, a solder reflow method. Since the Ni alloy has higher solder wettability than stainless steel, the solder fillet 12 can be appropriately formed. Therefore, the bonding strength of the plurality of protruding members 8 can be increased. The projecting member 8 has an inclined surface 8 a that comes into surface contact with the hole 1 a, whereby the frame case 1 is electrically connected to the ground terminal 9 via the projecting member 8.

  Next, the operation of the image reading apparatus A will be described.

  First, when each LED chip 6 emits light, the light 11 travels in the illumination optical path 14 toward the transparent cover 2 and is irradiated onto the surface of the document D through the document table T. When the light 11 reaches the document D, it is reflected by the surface of the document D, passes through each lens 31 of the lens array 3, and is received by each light receiving element 70 built in the sensor IC chip 7. . As a result, images of the document D are formed on the plurality of light receiving elements 70, and image signals from the respective light receiving elements 70 are processed to obtain read images.

  The pair of projecting members 8 and the plurality of sensor IC chips 7 are both mounted on the wiring pattern, and their positional relationship is accurate. By fitting the pair of projecting members 8 and the pair of holes 1a formed at accurate positions in the frame case 1, the positions of the plurality of sensor IC chips 7 with respect to the frame case 1 are also accurate. . Therefore, if the frame case 1 is attached with a predetermined position on the outer surface formed with high accuracy aligned with a predetermined position on the movable frame F of the scanner Sc, for example, the position in the scanner Sc is set to be high. The positions of the plurality of sensor IC chips 7 in Sc can be made accurate.

  When the plurality of light receiving elements 70 mounted on the plurality of sensor IC chips 7 are arranged at a predetermined accurate position in the scanner Sc, as clearly shown in FIG. 3, depending on the positions of the plurality of light receiving elements 70. The position of the readable area Sa in the defined main scanning direction with respect to the scanner Sc is also accurate. Such a readable area Sa is less likely to be largely shifted from the maximum reading area Sx of the scanner Sc, and the surplus portions Sm1 and Sm2 included in the readable area Sa may be smaller than the conventional one. Is possible. Therefore, the number of sensor IC chips 7 can be minimized, and the cost can be suppressed. Further, since the amount of signal from the light receiving element 70 is reduced, the time required for the image reading process can be shortened. Furthermore, the size of the image reading apparatus A in the main scanning direction is suppressed, which is advantageous for reducing the size of the scanner Sc, for example.

  In the present embodiment, the pair of protruding members 8 mounted on the wiring pattern are fitted into the pair of holes 1a, thereby positioning the sensor IC chip 7 in the frame case 1. Therefore, unlike the conventional case, even if an error occurs in the outer shape accuracy of the substrate 5 and the relative position between the substrate 5 and the wiring pattern, they are not affected by these. Therefore, it is not necessary to finish the outer shape of the substrate 5 with high accuracy, and the requirement for the positional accuracy of the wiring pattern on the substrate 5 can be relaxed, so that an improvement in productivity can be expected.

  In the present embodiment, since the frame case 1 has magnetic permeability, it is possible to suitably shield electromagnetic waves from above the image reading apparatus A, and electromagnetic waves can be prevented from leaking below the frame case 1. Therefore, the sensor IC chip 7 is less likely to be adversely affected by the electromagnetic wave, which is suitable for preventing malfunction. If the frame case 1 is used as a shield member, it is not necessary to provide a new member for shielding, the cost is reduced, the light 11 from the document D is shielded, and the image reading apparatus A is increased in size. There are no problems.

  Further, the frame case 1 has conductivity, and a part of the frame case 1 is grounded by being brought into surface contact with the plurality of protruding members 8 to be fitted. Therefore, the frame case 1 is not excessively charged even when the shield function is exhibited, and the sensor IC chip 7 and other IC chips arranged around the image reading apparatus A malfunction. Can be prevented.

  The image reading device provided by the present invention is not limited to the above embodiment.

  In the said embodiment, although the projection member 8 is made into the substantially cone shape which made the upper part the chamfered shape, this invention is not limited to this. For example, as shown in FIG. 5, it is good also as a shape which has the flange part 82 and the substantially cylindrical part 83 made into diameter smaller than this flange part 82. As shown in FIG. This protruding member 8 is fitted in a hole 1a provided in the frame case 1 as in the above embodiment. Further, as clearly shown in the figure, the upper side surface of the substantially cylindrical portion 83 is in surface contact with the hole 1a, and the horizontal position of the protrusion 8 with respect to the frame case 1 is defined. The upper surface of the substantially cylindrical portion 83 is in surface contact with the hole 1 a, and the vertical position of the protrusion 8 with respect to the frame case 1 is defined. Even with such a configuration, the same effect as in the above embodiment can be obtained. In addition, any shape that is suitable for positioning, such as a prism shape, a pyramid shape, or a cone shape, may be used. The frame case 1 can be configured to fit with a plurality of projecting members by forming a groove or a recess in addition to the hole. Further, the protruding member may be configured such that the core material itself is formed of a Ni alloy without providing a plating layer, for example. Even with such a configuration, the same effect as in the above embodiment can be obtained. The material of the core material and the plated layer is not limited to the above materials, and can be formed from various materials suitable for exhibiting the function intended by the present invention.

  In the said embodiment, although it is set as the structure provided with a pair of protrusion member, this invention is not limited to this. If the configuration includes three or more projecting members, it can be expected that the sensor IC chip 7 is positioned more accurately with respect to the frame case 1.

  The material of the frame case is not limited to the above embodiment. The blending ratio of the material of the frame case in the above embodiment is an example, and can be changed within a range in which the function intended by the present invention is exhibited when the shielding property or conductivity of electromagnetic waves is provided. Also, various synthetic resins and their alloys can be used. Furthermore, it is not limited to a synthetic resin, and may be a metal frame case, for example. In addition to these, the frame case may include a main body portion made of synthetic resin using polycarbonate or the like and a metal film formed on the surface of the main body portion by, for example, electrolytic plating. Even in such a configuration, since the frame case has magnetic permeability and conductivity, the same effect as the above embodiment can be obtained.

  The image reading apparatus A in the above embodiment is an example used by being assembled in a flat bed type scanner. However, the image reading apparatus A is not limited to this, and can read an image such as a scanner that feeds an original by a so-called platen roller or a handy scanner. It can be widely used by being assembled in various devices.

It is sectional drawing which shows an example of the image reading apparatus which concerns on this invention. It is a disassembled perspective view which shows an example of the image reading apparatus which concerns on this invention. It is the III-III sectional view taken on the line of FIG. It is a principal part enlarged view of FIG. It is principal part sectional drawing which shows the other example of the image reading apparatus which concerns on this invention. It is sectional drawing which shows an example of the conventional image reading apparatus.

Explanation of symbols

A Image reading device 1 Frame case 1a Hole 2 Transparent cover 3 Lens array 5 Substrate 6 LED chip 7 Sensor IC chip 70 Light receiving element 8 Protruding member 9 Ground terminal (of wiring pattern)

Claims (8)

A substrate having a wiring pattern formed on the surface;
A plurality of light receiving elements mounted on the substrate;
A frame case attached to the substrate;
An image reading apparatus comprising:
A plurality of protruding members are mounted on the wiring pattern, and the positioning of the frame case and the wiring pattern is performed by fitting the plurality of protruding members and a part of the frame case. An image reading apparatus characterized by comprising: The image reading apparatus according to claim 1, wherein the plurality of protruding members are made of metal. The plurality of projecting members include a metal core and a plating layer formed on the surface of the core and having higher solder wettability than the core. The image reading apparatus described in 1. The image reading apparatus according to claim 1, wherein the frame case has magnetic permeability. The image reading apparatus according to claim 1, wherein the frame case has conductivity. The image reading apparatus according to claim 5, wherein the frame case has a metal film formed on a surface of a resin main body portion. The image reading apparatus according to claim 5, wherein any one of the plurality of protruding members is ground-connected. The image reading device according to claim 5, wherein the plurality of projecting members and a part of the frame case are in surface contact with each other.